Method for Manufacturing or Testing Metered-dose-ejection Devices and Testing Apparatus Therefore
For testing metered-dose-ejection devices, whether the ejected dose accords with a rated dose, the device (1) is sealingly applied (26) to a test compartment (24) and upon machine manipulation on the device (M, 5) a dose is ejected into the test compartment (24). Pressure difference established by such injection and with respect to a pre-established reference pressure (30) in the test compartment (24) is monitored by a pressure sensor (32). The output signal (o) of this sensor (32) is indicative of the extent of the addressed dose.
This application is a U.S. national phase application under 35 U.S.C. §371 of International Application No. PCT/EP2009/055206 filed Apr. 29, 2009.
DEFINITIONS
-
- We understand under a “metered-dose-ejection” (MDE) device a device with a receptacle which contains a liquid or powderous product. Such device further comprises a manually operable manipulator. By each action upon the manipulator—customarily an actuating stroke—there is ejected from the outlet opening of the receptacle a dose of fluidic material. The receptacle may contain a propellant gas, customarily in liquid form, so that upon each stroke on the manipulator the dose of the addressed fluid is ejected through the receptacle outlet, driven by the propellant gas and thus as a dose of gaseous fluid. In other techniques pressure necessary to eject the addressed dose of gaseous fluid is built up only by actuation of the manipulator e.g. in a fluidizing device applied to the MDE device.
- Still in other embodiments of such MDE the fluid content in the receptacle is pressurized in the recipient but only ejected as a gaseous fluid-dose with the help of an additional nozzle of a fluidizing device applied in the MDE.
- Irrespective of the technique which is applied at or to such an MDE to eject a product contained in the receptacle, common to all these devices is that by one actuation upon the manipulator one dose of product is ejected which dose contains a predetermined, rated amount of the MDE-content.
- A more specific category out of MDE devices are the so-called “metered-dose inhalers”, MDI. They do contain powderous or liquid product and a propellant gas. The ejection opening comprises a projecting, tubular stub. This stub acts as the manipulator addressed above in that moving the stub coaxially into and towards the interior of the receptacle provides for ejecting a product dose out of the tubular stub. Such MDIs are widely known for medical appliances as for anti-allergic products to be inhaled.
- We further understand under the generic term of a fluid:
- a gas
- a liquid
- a powder
- a gas containing liquid and/or powder
- We further understand under a gaseous fluid:
- a gas
- a gas containing powder and/or liquid
- Thus, in any case an MDI finally ejects a gaseous fluid, be it directly from the outlet of the receptacle or be it after respective treatment of a fluid from the receptacle within a fluidizer device.
Very often, the dose ejected by an MDE is critical with respect to its extent. This is especially and as an example the case for some medical products as from MDI devices to be applied in a well-controlled manner. MDE devices leaving manufacturing may be subject to relatively large tolerances with respect to a rated dose to be ejected or are even misassembled by combining a specific product contained in the receptacle with a wrong dosing manipulator or valve arrangement.
SUMMARYIt is an object of the present invention to provide MDE devices and thereby more specifically MDI devices the ejected dose of gaseous fluid being within predetermined limits equal to a rated dose.
This is achieved according to the present invention by a method of manufacturing metered-dose-ejection—MDE—devices with an affirmed rated ejection dose of gaseous fluid per ejecting manipulation. This method comprises:
-
- sealingly connecting the ejection outlet of an unaffirmed MDE to a test compartment,
- machine performing an ejection manipulation upon the manipulator of the MDE, thereby ejecting a dose of gaseous fluid into the test compartment;
- monitoring pressure in the test compartment after having established a predetermined volume of the test compartment containing the ejected dose of gaseous fluid;
- exploiting the pressure monitored as an indication of whether the ejected dose accords, within predetermined limits, with a predetermined rated ejection dose or not and
- if it does, affirming to the MDE device to eject doses which accord to the predetermined rated dose.
Thus and according to this method an MDE which has been manufactured but which is not affirmed to eject doses of a fluid which accord to rated doses of gaseous fluid per ejecting manipulation are subjected to a further manufacturing step, according to a dose testing step, so that finally MDE devices result which eject doses of fluid according to a rated dose, i.e. which are only different from such rated dose within predetermined limits.
It is thus also within the frame of the present invention to propose a method for testing MDE devices to establish whether they do eject a predetermined rated dose of gaseous fluid per ejection manipulation upon the device or not. Thereby, as was addressed above, MDE devices are addressed which directly do eject respective doses of gaseous fluid or which eject a fluid which is only converted to a gaseous fluid with the help of a fluidizer device which is customarily removably applied to the receptacle. It is perfectly clear that in this latter case the method for manufacturing as addressed above as well as the method for testing as here addressed comprise the application of a respective fluidizer device to the MDE device. The method for testing as addressed comprises
-
- sealingly connecting the outlet of the MDE device to a test compartment;
- machine performing an ejection manipulation upon the MDE device, thereby ejecting a dose of gaseous fluid into the test compartment;
- monitoring pressure in the test compartment after having established a predetermined volume of the test compartment;
- exploiting the pressure monitored as an indication of whether the ejected dose accords, within predetermined limits, with the predetermined rated ejection dose or not.
In one embodiment of either methods, namely the method for manufacturing and the method for testing as addressed above, the test compartment comprises a piston/cylinder arrangement and further comprises machine performing the ejection manipulation by means of a movement of the piston relative to the cylinder of the piston/cylinder arrangement, departing from a predetermined relative position of the piston and cylinder and monitoring the pressure after return of the piston and cylinder in the predetermined relative position.
Thereby, this embodiment is especially suited for manufacturing or testing MDI devices whereat the ejection manipulation is performed by pushing a tubular outlet stub into the receptacle of the MDI device. By the fact that pressure monitoring is only established after the piston and cylinder have returned in their predetermined relative position it is made sure that such monitoring is always performed in a volume of predetermined, reference extent which is established by the addressed piston/cylinder arrangement when piston and cylinder are positioned in the addressed predetermined relative position.
In a further embodiment of the method as addressed above, which may be combined with all of the embodiments addressed to now as well as with those which will be addressed subsequently, there is machine performed at least one flushing manipulation, thereby generating respectively at least one flushing dose ejection before machine performing the one manipulation for ejecting that dose which is checked by pressure monitoring. Thereby, there is prevented that the at least one flushing dose does influence the pressure as monitored.
Thereby, one or more than one flushing doses are ejected from the MDE device before causing that dose to be ejected which is to be checked. Clearly in a most simple way the flushing doses are ejected into the test compartment too. Nevertheless, to prevent any influence of the pre-ejected flushing doses upon the measuring result, reference pressure is re-established in the test compartment after flushing. Reference pressure is customarily ambient pressure. In other words and making use of ambient pressure as reference pressure for pressure monitoring, after each or after a predetermined number of flushing dose ejection or even permanently during such flushing, the test compartment is open to ambient and if necessary pumped, before the test compartment is sealingly closed at reference pressure, establishing start condition for checking the respective MDE device.
In a further embodiment of the manufacturing and testing methods according to the invention, which further may be combined with any of the embodiments addressed to now and as will be addressed subsequently, the MDE device to be tested is machine-shaken before performing machine manipulation to eject the dose to be tested, thereby also preferable before performing flushing.
The shaking operation, which may be performed by all-around rotating the respective device or by oscillatingly swivelling the device about a predetermined swivelling angle, or which may be performed by linear shaking or in combination, the content of the MDE device is brought to the state as it has to be customarily brought for practical use.
Still in a further embodiment of the manufacturing as well as of the testing method according to the invention and which further may be combined with any of the already addressed as well as with any of the subsequently addressed embodiments, at least the dose ejected upon the one machine manipulation is subjected to filtering downstream the outlet of the MDE device. Clearly and if, as addressed above, flushing doses are ejected into the test compartment such filtering is also performed with respect to the addressed flushing doses. Thereby, it is prevented that ejected droplets or powder particles of the gaseous fluid accumulate to the inner surfaces of the test compartment, to the sensing surface of a pressure sensor, are penetrating into a pump etc., so that by such filtering the time period or operating cycles of the respective testing arrangement up to cleaning are significantly enlarged. Thereby, the addressed filtering is performed by a filtering member which is easily removed and replaced.
Still in a further embodiment of the manufacturing or the testing methods according to the present invention, which further may be combined with any of the already addressed embodiments as well as with the embodiments subsequently addressed, the method is performed upon a stream of subsequently conveyed MDE devices. Thus, the method according to the invention under all its aspects is perfectly suited for in-line testing and manufacturing MDE devices which are conveyed to a respective testing station or—machine with multiple testing stations in a stream and at high velocity.
Still in a further embodiment of the manufacturing as well as of the testing method according to the invention, which may be combined with all of the addressed embodiments, the MDE device is an MDI device.
The object upon which the present invention is based is further resolved by an apparatus for testing metered-dose-ejecting—MDE—devices, whether they do eject a predetermined rated ejection dose of gaseous fluid per ejection manipulation upon the device or not, within predetermined deviation limits with respect to the addressed rated ejection dose, which apparatus comprises:
-
- a support for at least one MDE device;
- a driven manipulator for causing the MDI device on the support to eject a dose of fluid from an ejection outlet;
- a driven connector arrangement to be automatically sealingly applied to the ejection outlet and establishing flow communication of the ejection outlet to an inlet for gaseous fluid into a test compartment;
- a pressure sensor with its sense input in flow communication with the interior of the test compartment.
In one embodiment of the addressed apparatus, which may be combined with all of the subsequently addressed embodiments, the apparatus is intended for testing MDE devices having a pressurized content and an outlet valve which is opened by moving a tubular, spring-biased outlet stub axially towards the interior of the receptacle of the device. According to this embodiment the support comprises a gripping member for gripping the MDE device and holding the device with the stub in a predetermined position. The test compartment comprises a piston/cylinder arrangement with a piston drivingly operable within the cylinder and coaxially to the stub in the addressed predetermined position. The cylinder has a front wall with a through-bore for the stub in the addressed predetermined position. There is further provided a drive arrangement which establishes a first relative movement of the gripping member and of the piston/cylinder arrangement so as to sealingly bias the device to the outer surface of the front wall and thereby forming the addressed driven connector arrangement while introducing the stub into the through-bore. The addressed drive arrangement further establishes for a movement of the piston, as the addressed driven manipulator, from a predetermined reference position within the cylinder towards the front wall and towards and onto the stub in the through-bore. Thereby, the stub is moved towards the interior of the device's receptacle. The addressed drive arrangement further establishes for a back movement of the piston in the cylinder, back into the predetermined reference position.
The cylinder and piston which form the test compartment define a first compartment volume in flow communication with the outlet stub, as the addressed stub is moved towards the interior of the recipient. They further define in the addressed predetermined position of the piston within the cylinder a second compartment volume in flow communication with the first cavity volume and with the sense input of the pressure sensor.
By this embodiment, in operation, the MDE device is gripped and sealingly biased towards the outer surface of the front wall of the piston/cylinder arrangement. Thereby, the tubular stub is passed through the through-bore in the addressed front wall. Thereafter, by relative movement of the piston within the cylinder, thereby still keeping sealing engagement of the device with the front wall of the piston/cylinder arrangement, the tubular stub of the device is pushed towards the interior of the device's receptacle, thereby causing a dose of fluid to be ejected into the addressed first volume of the test compartment. It is only after the piston and cylinder have re-assumed their predetermined relative position, thereby establishing for the second volume in flow communication with the first volume that a relevant pressure measurement is made. Thereby, the sum of first volume and second volume accord with a predetermined reference volume to establish dose-significant pressure measurement.
In one embodiment of the embodiment which was just addressed the piston has a further through-bore with an opening aligned with the through-bore of the front wall and abutting in a backspace cavity volume within the piston.
Thus, by means of the addressed backspace cavity in the piston there is established a cavity volume which is independent of the relative position of piston and cylinder. Because the piston is moved back into a predetermined reference position with respect to the cylinder, the variable volume established between the piston and the cylinder becomes in this predetermined relative position independent of the stroke performed by the piston within the cylinder. Thereby, for pressure monitoring in the addressed predetermined reference position an accurate constant reference volume is established.
In a further embodiment, which may be combined with any of the already addressed embodiments and embodiments still to be addressed, there is provided a filter member downstream the addressed connector in the test compartment.
With an eye on the embodiment with the backspace cavity volume in the piston and a through-bore aligned with the through-bore in the front wall and abutting in the addressed backspace cavity, it becomes evident that such filter element is preferably provided at the end of the through-bore in the piston abutting in the backspace cavity.
In a further embodiment of the just addressed embodiment the filter member is a replace part.
Still in a further embodiment of the apparatus according to the invention, which may be combined with all embodiments addressed to now as well as with the embodiments to be addressed, the support for the MDE device is drivingly shakeable.
Thereby, in one embodiment of realizing shakeability, the addressed support is drivingly swivellable about an axis, thereby preferably oscillatingly swivellable by a predetermined swivel angle.
In one embodiment the apparatus according to the invention and according to each and all embodiments as were addressed is tailored for testing MDI devices.
The invention shall now be further described by means of examples and with the help of figures.
The figures show:
The addressed dose is thereby ejected by some types of MDE devices according to
At the second type of MDE devices as schematically shown in
The
An MDI device, metered-dose-inflator, is a special type of MDE device and may be constructed according to the MDE type of
This type of MDI device thus accords with the more generic type of MDE device of
The type of MDI device according to
With the help of
To increase significance of the measurement as performed according to the present invention it might be desirable to first eject from the MDE device under test one or more than one flushing doses before ejecting that dose which shall be subjected to pressure measurement. As schematically indicated in
In a further generic embodiment it is taken into account that often an MDE device has to be shaken before a proper representative dose of product is ejected. In these cases the addressed requirement is considered by providing a shaking drive (not shown in
As has been addressed above, the generic principle of the present invention has been explained with the help of
As shown in dashed lines, the receptacle 1 of an MDI device is first gripped by a support member 20 as of
Thereafter, the MDI device with tubular outlet stub 13 is brought into a predetermined position wherein tubular stub 13 is coaxial with a receiving through-opening 45 in a front plate 47 of a piston/cylinder arrangement to be described.
By means of drive 22 according to
The stub 13 projects as shown out of the trough-bore 45 towards the interior of the piston/cylinder arrangement generically denoted by 50. The piston/cylinder arrangement comprises a cylinder 51 which is closed by the front plate 47. Within the cylinder 51 there is drivingly propelled a piston 53, sealed with respect to the inner surface of cylinder 52 as schematically shown by seals 55 in a customary manner for sealing pneumatic pistons. The cylinder 51 comprises a rim portion 57 which forms a stop for a respective shoulder 59 of the piston, thereby establishing a predetermined lower reference position between cylinder 51 and piston 53. Coaxially to the through-bore 45 and thus to the tubular stub 13 of the MDI device introduced, the piston has a bore 61 open towards and aligned with through-bore 45 and abutting into a piston cavity 63. As further schematically shown in
After the MDI device having been shaken and introduced into the through-bore 45 of front plate 47, the piston within cylinder 51 is risen by means of drive 51. Thereby, the end of tubular stub 13 comes in contact with the rim of bore 61 and is pushed upwards into the receptacle 1 of the MDI device. Thus, a dose of product is ejected from the MDI device through the inwards moved tubular stub 13, via bore 61 within piston 53 into the piston cavity 63. The piston 53 is retracted by drive 51 up to the stop 57/59 and the pressure in the piston cavity 63 is measured. Thereafter, line 71 is opened by opening valve 73 to discharge the overpressure in piston cavity 63 and to re-establish therein ambient pressure as a reference pressure for testing the next MDI device.
If one or more than one flushing doses shall be ejected before measurement, the piston 53 is risen and retracted one or more than one time to cause by respective action upon the tubular stub 13 the MDI device to eject one or more than one flushing doses into the piston cavity 63. Between each of the flushing dose-ejecting operations, line 71 is opened by means of controlled valve 73 and, after opening valve 69, the piston cavity is flushed. It is only after re-closing valve 73, stopping pump 67 and closing valve 69 that the piston 53 is risen, this time for causing a “testing” dose to be ejected which is monitored by sensor 65. The result of this monitoring is exploited as an indication whether the injected dose accords with a rated dose within limits e.g. as was addressed in context with
If instead of an MDI according to the
Further, the overall arrangement which is shown in
A multitude of testing apparatus or stations as most generically explained with the help of
Finally, it must be emphasized that a device with a manipulator for continuously ejecting a fluid product may be operated as an MDE device by time controlling the duration of such manipulation. Clearly such devices operated as an MDE device are also addressed by the term “MDE” as of the present invention. In this case the rate of product output from such device per time unit is tested according to the invention, and the term “dose” is to be understood as “ejected material amount per time unit”.
Claims
1. A method of manufacturing metered-dose-ejection—MDE—devices with an affirmed rated ejection dose of fluid upon an ejecting manipulation comprising:
- sealingly connecting the ejection outlet of an unaffirmed MDE device to a test compartment;
- machine performing an ejection manipulation upon said MDE device, thereby ejecting a dose of said fluid as a gaseous fluid into said test compartment;
- monitoring pressure in said test compartment after having established a predetermined volume of said test compartment;
- exploiting said pressure monitored as indication of whether said ejected dose accords within predetermined limits with said predetermined rated ejection dose or not;
- if it does, affirming to said receptacle to eject doses according to said predetermined rated dose.
2. A method of testing metered-dose-ejection—MDE—devices whether they do eject a predetermined, rated ejection dose of fluid upon an ejection manipulation or not, comprising:
- sealingly connecting the outlet of an MDE device to a test compartment;
- machine performing a ejection manipulation upon said MDE device, thereby ejecting a dose of said fluid as a gaseous fluid into said test compartment;
- monitoring pressure in said test compartment after having established a predetermined volume of said test compartment;
- exploiting said pressure monitored as indication of whether said ejected dose accords within predetermined limits with said predetermined rated ejection dose or not.
3. The method of claim 1 or 2, said test compartment comprising a piston/cylinder arrangement and comprising machine performing said ejection manipulation by means of a movement of a piston relative to a cylinder of said piston/cylinder arrangement, departing from a predetermined relative position, and monitoring said pressure after return of said piston and cylinder in said predetermined relative position within a compartment of said piston/cylinder arrangement.
4. The method of one of claims 1 or 2, further comprising machine performing at least one flushing manipulation, thereby generating respectively at least one flushing dose ejection before machine performing said one manipulation and thereby preventing said at least one flushing dose to influence said pressure monitored.
5. The method of one of claims 1 or 2, further comprising machine shaking said MDE device before performing said one machine manipulation.
6. The method of one of claims 1 or 2, further comprising filtering doses ejected at an inlet for said ejected doses to said test compartment.
7. The method of one of claims 1 or 2 being performed upon a stream of subsequently conveyed MDE devices.
8. The method of one of claims 1 or 2, said MDE device being a metered-dose inhaler—MDI—device.
9. Apparatus for testing metered-dose-ejecting—MDE—devices whether they do eject a predetermined rated ejection dose of fluid upon an ejection manipulation or not, comprising:
- a support for at least one MDE device;
- a driven manipulator for causing said MDE device on said support to eject a dose of fluid from an ejection outlet;
- a driven connector arrangement to be automatically and sealingly applied to said ejection outlet and establishing flow communication with a test compartment cavity;
- a pressure sensor with its sense input in flow communication with said test compartment cavity.
10. The apparatus of claim 9 for testing MDE devices having an outlet valve being opened by moving a tubular spring-biased outlet stub axially towards the interior of said device,
- said support comprising a gripping member for gripping the MDE device and holding said device with said stub in a predetermined position;
- said test compartment comprising a piston/cylinder arrangement with a piston drivingly operable within a cylinder and coaxially to said stub in said predetermined position, said cylinder having a front wall with a through-bore for said stub in said predetermined position;
- a drive arrangement establishing a first relative movement of said gripping member and said piston/cylinder arrangement so as to sealingly bias said device to the outer surface of said front wall while introducing said tubular stub into said through-bore and further to establish a second movement of said piston from a predetermined reference position within said cylinder in said cylinder towards said front wall and towards and onto said tubular stub in said through-bore so as to move said stub towards said interior of said receptacle and still further establishing a back movement of said piston in said cylinder back into said predetermined reference position;
- said cylinder and piston defining in said predetermined reference position a test compartment cavity of predetermined volume being in flow communication with said sense input of said pressure sensor.
11. The apparatus of claim 10, said piston having a further through-bore with an opening aligned with said through-bore in said front wall and abutting in a backspace cavity in said piston.
12. The apparatus of one of claims 9 to 11, further comprising a filter member downstream said connector arrangement and upstream at least a part of said test compartment cavity.
13. The apparatus of claim 12, said filter member being a replace part mounted within said piston.
14. The apparatus of one of claims 9 to 11, said support being drivingly shakeable.
15. The apparatus of claim 14, said support being drivingly swivellable about an axis.
16. The apparatus of one of claims 9 to 11 for testing metered-dose-inhaler—MDI—devices.
17. A method according to one of claims 1 or 2 or an apparatus according to one of claims 9 to 11 wherein said MDE device is established by a device for continuous ejection of a product upon ongoing operation of a manipulator and by monitoring or predetermining a manipulation time span.
Type: Application
Filed: Apr 29, 2009
Publication Date: Feb 16, 2012
Patent Grant number: 8336397
Inventor: Martin Lehmann (Wohlen)
Application Number: 12/521,213
International Classification: G01F 1/34 (20060101); B23P 11/00 (20060101);